1. Field of the Disclosure
The present disclosure relates to a power generation input device which can generate power according to an operating force from the outside, and to an electronic apparatus where a transmitting operation or the like is performed according to the electromotive force of the power generation input device when it is operated.
2. Description of the Related Art
In FIG. 7 of Japanese Unexamined Patent Application Publication No. 2009-199961, a basic structure of a self-power generating type key input device is disclosed.
The key input device includes a core forming a magnetic path and a coil portion wound on the core. Both ends of the core are opposed to each other via a space and a rod-shaped magnet can be interposed in the space. The electromotive force is generated in the coil from the change of magnetic flux in the core when the magnet is interposed in the space and change of the magnetic flux in the core when the magnet is withdrawn from the space.
The key input device disclosed in Japanese Unexamined Patent Application Publication No. 2009-199961 is moved in or out of the space without changing the orientation of the magnetic poles of the magnet. Thus, the orientation of the magnetic flux in the core is not reversed, an amount of change of the magnetic flux in the core is small and the power generation efficiency is poor.
In the structure, when the magnet is inserted in the space, the magnet is attracted to an end of the core and moves at a relatively fast speed; however, when the magnet is withdrawn from the space, since a force acts in an orientation where the magnet is prevented from withdrawing from the magnet, there is a limit to the speed up the withdrawal. Since the electromotive force is proportional to the change per unit time of the magnetic flux in the core, the electromotive force that is induced when the magnet is withdrawn from the space decreases greatly compared to the electromotive force that is induced when the magnet is moved into the space. In order to increase the electromotive force, a return spring is required to exert a strong force to withdraw the magnet from the space; however, the force of the return spring acts as a resistance against the operating force and the device is hard to operate.
The transducer disclosed in FIGS. 3 and 4 of U.S. Patent Application Publication No. 2006/0091984 A1, is provided with stop points opposed to each other at both ends of the soft-magnetic member on which the coil is wound. A permanent magnet is supported so as to rotate freely around its axis between the soft-magnetic members, and a first magnet layer and a second magnet layer are stacked on both surfaces of the permanent magnet. Both ends of the first magnet layer and both ends of the second magnet layer are opposed to each other in parallel, and the stop points of the soft magnetic element are inserted therebetween.
When the permanent magnet rotates in the clockwise direction, one end of the first magnet layer and one end of the second magnet layer are magnetically attracted and fixed to the stop points of the soft magnetic member, and when the permanent magnet rotates counterclockwise, the other end of the first magnet layer and the other end of the second magnet layer are magnetically attracted and fixed to the stop points of the soft magnetic member. The transducer also generates the electromotive force to the coil with the change of the magnetic flux in the soft magnetic member when the permanent magnet rotates in the clockwise direction and with the change of the magnetic flux in the soft magnetic member when the permanent magnet rotates in the counterclockwise direction.
Since the first magnet layer and the second magnet layer are attracted and fixed to the soft magnetic member in both directions when the permanent magnet rotates in the clockwise direction and in the counterclockwise direction, the transducer disclosed in U.S. Unexamined Patent Application Publication No. 2006/0091984 A1, requires an excessively large force to rotate the permanent magnet from the attracted and fixed state in the reverse direction. The transducer is provided with a return spring for returning the permanent magnet to the same posture, and in this regard, U.S. Patent Application Publication No. 2006/0091984 A1 describes that a return spring has to be used which exerts a force greater than the magnetic holding force at the stop point. Accordingly, when the permanent magnet rotates, a force is required which combines a force that is required to separate the first magnet layer and the second magnet layer from the stop point and a force that resists the return spring. If an excessive operating force is not provided, the device cannot be operated.